1. Field of the Invention
The present invention relates generally to the field of automatic guns and more particularly to automatic cannon.
2. Discussion of the Prior Art
Automatically firing guns can be generally classified as either self-powered or externally-powered. Self-powered guns, which include most automatic small arms and many types of automatic cannon, typically employ high pressure gases generated by firing for their automatic operation. Upon firing, the high pressure barrel gases of such guns are used to drive a bolt (bolt group) rearwardly from the breech at a high recoil velocity. The recoiling bolt extracts, or helps to extract, the just-fired shell casing from the breech and subsequently causes ejection of the casing from the gun. On counter-recoil, normally after impacting some type of recoil buffer, the bolt strips an unfired shell from an associated feeder or magazine and rams the shell forwardly into the firing chamber. Typically the chambered shell is fired automatically when the bolt reaches, and temporarily locks to, the breech. Firing is stopped by searing up the bolt at a rearward position in readiness for a next firing; springs drive the bolt forwardly to reinitiate firing upon unsearing. Exemplary of such gas-operated, automatic guns is the open framework receiver cannon disclosed in my prior U.S. Pat. No. 4,269,109.
Some other types of self-powered automatic guns utilize recoil forces caused by the gun's firing for operation. Firing recoil forces drive the bolt rearwardly in recoil; otherwise, gun operation is typically the same as for gas-operated automatic guns. Still other types of automatic guns may use both the high pressure gases and recoil forces from firing for automatic operation.
For such reasons as easy portability and compactness, virtually all automatic (and semi-automatic) small arms are self-powered. Some gas or recoil operated automatic cannon may use external power for shell feeding; nevertheless, such guns are usually still considered to be self-powered. Self-powered guns, however, have some disadvantages. As an illustration, because operation of self-powered guns depends upon firing of the gun, failure of a shell to fire, as may sometimes occur, causes the gun to stop firing. Moreover, if shell feeding is slow for any reason and there is no shell in position for the counterrecoiling bolt to pick up, firing stops. Furthermore, self-powered automatic guns are difficult to properly time because of different characteristics of different types of shells which may be fired in the gun, and because of shell-to-shell variations in any one type of shell being fired. When gun operation is not properly timed, unexpectedly high parts stress may occur and/or firing accuracy may be adversely affected. Good self-powered gun design must ordinarily take into account worst case timing conditions and performance may, therefore, be somewhat compromised.
In contrast, the operations of shell loading, firing, extraction and ejection of externally-powered automatic guns are performed by such externally provided forces as electric, hydraulic or air motors, the operations being, therefore, completely independent of actual shell firing. Any shells which fail to fire are automatically extracted and ejected without otherwise affecting the gun's firing operation. Moreover, proper timing is easier to attain in externally-powered automatic guns than in self-powered guns because of the independence on firing. For such reasons, higher firing rates can typically be attained in externally-powered guns than in comparable self-powered automatic guns.
An example of externally-powered, automatic guns is the modern Gatling gun, which employs several, usually three to six, gun barrels mounted together around a small circle, through the center of which passes a barrel rotational axis. In response to an external motor spinning the barrel assembly at a high rotational velocity, camming mechanisms cause shell loading, firing, extraction and ejection. Such guns have extremely high firing rates since they are constructed so that while one barrel is firing, another or others are being loaded, while shells are being extracted from still other barrels. A disadvantage of this particular type automatic gun is that it uses relatively complicated mechanisms and so is relatively expensive to produce and to maintain.
Depending upon the particular military weapons system involved, a self-powered or an externally-powered automatic gun may be preferred and/or specified. Typically self-powered automatic cannon are preferred for lightweight, mobile, land-based gun systems, so as to avoid the added weight and complexity of external gun-drive apparatus. However, for many other critical weapons systems, such as those used in airborn applications, externally-powered guns may be preferred because of their normally higher firing rates and potentially greater reliability of operation.
However, because of the obvious criticality of weapons systems using automatic cannon, and as a result of the necessity to continually upgrade gun performance standards so as to compensate for improvements in enemy weaponry, design improvements are continually needed to enhance gun performance while at the same time reducing size, weight, cost and complexity and increasing gun maintainability, reliability and service life.
Along with improvements to the guns themselves, continual improvements to ammunition used by these guns are also needed, with much current effort in this regard being directed towards development of cylindrical, telescoped shells wherein the projectile is fully disposed within the casing and surrounded by propellant. Such shells are substantially larger in diameter than conventional shells of corresponding calibre but are much shorter, thereby enabling correspondingly shorter bolt strokes and faster gun operation. Due to their uniform shape, feeding of cylindrical shells is also usually simpler than the feeding of conventional shells, and shell magazine packing densities can, for the most part, be substantially increased when cylindrical shells are used.
It is therefore, one object of the present invention to provide an automatic gun, for firing cylindrical, telescoped ammunition, which has relatively few parts so as to be comparatively less expensive to construct and maintain and comparatively more reliable than heretofore available automatic guns.
Another object of the present invention is to provide an automatic gun, for firing cylindrical, telescoped ammunition, having a barrel which axially rotates with other rotating parts of the gun during firing of the gun.
Still another object of the present invention is to provide an externally-powered, automatic gun, for firing cylindrical, telescoped ammunition, having a barrel and having a chamber which slides radially as it rotates with the barrel in such a manner that the longitudinal axis of a shell held in the chamber is aligned for a preselected dwell time with the bore axis of the barrel at the time of firing.
A further object of the present invention is to provide an automatic gun, for firing cylindrical, telescoped ammunition, having a rotating barrel and a rotating and radially sliding chamber, a shell cavity of which is constrained to travel along a cardioid-shaped path, the cavity being aligned with the barrel at the cusp of the curve for shell firing, and elsewhere along the curve being out of alignment with the barrel so that shell loading and shell extraction operations can be performed.
Other objects, features and advantages of the present invention will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.